Objective: To evaluate factors that may contribute to the increased stroke case fatality rates observed in individuals from low-income areas.
Methods: We conducted a cohort study on a population-based sample of all patients with stroke or TIA seen at 153 acute care hospitals in the province of Ontario, Canada, between April 1, 2002, and March 31, 2003, and April 1, 2004, and March 31, 2005. Socioeconomic status measured as income quintiles was imputed from median neighborhood income. In the study sample of 7,816 patients we determined 1-year mortality by grouped income quintile and used multivariable analyses to assess whether differences in survival were explained by cardiovascular risk factors, stroke severity, stroke management, or other prognostic factors.
Results: There was no significant gradient across income groups for stroke severity or stroke management. However, 1-year mortality rates were higher in those from the lowest income group compared to those from the highest income group, even after adjustment for age, sex, stroke type and severity, comorbid conditions, hospital and physician characteristics, and processes of care (adjusted hazard ratio for low- vs high-income groups, 1.18; 95 confidence interval 1.03 to 1.29).
Conclusions: In Ontario, 1-year survival rates after an index stroke are higher for those from the richest compared to the least wealthy areas, and this is only partly explained by age, sex, comorbid conditions, and other baseline risk factors.